Function fadroma::tokens::convert

pub fn convert(
    amount: impl Into<Uint256>,
    rate: impl Into<Uint256>,
    input_decimals: u8,
    output_decimals: u8
) -> StdResult<Uint256>

Convert between tokens with different decimals.

Arguments

• amount - the amount of input token to convert
• rate - corresponds to the output token decimals. E.g: If we want 1:1 rate and the output token has 6 decimals, then rate = 1_000_000
• input_decimals - the number of decimals of the input token
• output_decimals - the number of decimals of the output token

Examples

Assuming the user friendly (in the UI) exchange rate has been set to 1 output_token (9 decimals) == 1.5 input_token (6 decimals): the rate would be 1 / 1.5 = 0.(6) or 666666666 (0.(6) ** 10 * 9) meaning the price for 1 output_token is 1500000000 (1.5 * 10 ** 9 decimals) of input_token.

If we want to get 2 of output_token, we need to send 3 input_token i.e. amount = 3000000000 (3 * 10 ** 9 decimals)

use fadroma::tokens::convert;
use fadroma::cosmwasm_std::Uint256;
 
let rate = 666_666_666u32;
let amount = 3_000_000u32;

let result = convert(amount, rate, 6, 9).unwrap();
assert_eq!(result, Uint256::from(1_999_999_998u32));